Commercial insurance formularies are slowing the adoption of lower-emission inhalers for asthma and COPD, according to a study published in JAMA Network Open. Researchers led by Soko Setoguchi of the Rutgers RWJBarnabas Center for Climate, Health, and Healthcare analyzed 31,219 commercial plans and found that propellant-free dry-powder and soft-mist inhalers were covered less often and with more administrative hurdles than traditional metered-dose inhalers, which use hydrofluoroalkane propellants that contribute to greenhouse gas emissions.
The coverage gap was starkest for short-acting bronchodilators: 66.4% of plans covered only a metered-dose inhaler with no propellant-free alternative. While more than 99% of plans covered at least one inhaled corticosteroid and one combination inhaler, propellant-free versions were covered by 89.5% and 82.6% of plans, respectively. On preferred tiers without prior authorization or step therapy, metered-dose inhalers had near-universal coverage across all three drug classes, while propellant-free versions lagged far behind—just 7.8% for short-acting bronchodilators, 61.8% for inhaled corticosteroids, and 52.2% for combinations.
The authors argue that availability is not the problem, since many low-emission inhalers are approved and on the U.S. market; rather, formulary design is the main barrier. They point to the Veterans Health Administration, which cut inhaler-related emissions by 68% from 2008 to 2023 after a 2021 formulary change, though a prior VA study found a small increase in emergency and hospital care after switching devices. The researchers recommend placing at least one propellant-free option per class on preferred tiers and minimizing utilization management, while noting that European guidance favors shared decision-making over blanket substitution.